This sheet is about exposure to meclizinein pregnancy and while breastfeeding. This information is based on published research studies. It should not take the place of medical care and advice from your healthcare provider.

What is meclizine?

Meclizine is a medication that has been used to treat nausea and vomiting, motion sickness, and vertigo (a feeling of whirling and loss of balance). It belongs to a class of medications called antihistamines. Meclizine is available over the counter and by prescription. Some brand names for meclizine are Antivert®, Bonine®, Meclicot®, and Dramamine®.

Sometimes when womenfind out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take your medication. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy.MotherToBaby has a fact sheet on nausea and vomiting in pregnancy here https://mothertobaby.org/fact-sheets/nausea-vomiting-pregnancy-nvp/.

I take meclizine. Can it make it harder for me to get pregnant?

Studies have not been done to see if taking meclizinecan make it harder to get pregnant.

Does taking meclizineincrease the chance of miscarriage?

Miscarriage is common and can occur in any pregnancy for many different reasons.When used as directed, meclizine is not expected to increase the chance of miscarriage.

Does taking meclizineincrease the chance of birth defects?

Birth defects can happen in any pregnancy for different reasons.Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect.We look at research studies to try to understand if an exposure, like meclizine, might increase the chance of birth defects in a pregnancy. Most studies do not suggest an increase in birth defects with use of meclizine during the first trimester. This includes a large looking at over 16,000 pregnancies exposed to meclizine in the first trimester.

Does taking meclizine in pregnancy increase the chance of other pregnancy-related problems?

It is not known if meclizinecan increase the chance ofother pregnancy-relatedproblems, such as preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth). One large looking at over 16,000 pregnancies exposed to meclizine in the first trimester found no increased chance of preterm birth, low birth weight, short body length, and small head circumference after exposure to meclizine.

Does taking meclizinein pregnancy affect future behavior or learning for the child?

It is not known if meclizineincreases the chance for behavior or learning issues for the child.

Breastfeeding while taking meclizine:

There is no information on meclizine use while breastfeeding.If you suspect that the baby has symptoms (such as drowsiness, irritability,or dry mouth), contact the child’s healthcare provider.

It is possible, but not proven,that antihistaminesmight lower the amount of breast milk a person makes. This might be more likely to happen if antihistamines are used together with an oral decongestant like pseudoephedrine (Sudafed®), or if used before breastfeeding is fully established (when a baby is first born). Be sure to talk to your healthcare provider about all your breastfeeding questions.

If a man takesmeclizine, could it affect fertility or increase the chance of birth defects?

Studies have not been done to see if meclizine could affect men’s fertility (ability to get a partner pregnant) or increase the chance of birth defects. In general, exposures that fathers or sperm donors have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.

Selected References:

• Gilboa SM, et al. 2009. National Birth Defects Prevention Study: Use of antihistamine medications during early pregnancy and isolated major malformations. Birth Defects Res A Clin Mol Teratol. 85(2):137-150. [PMC free article: PMC3619228] [PubMed: 19161158]
• Gilboa SM, et al. 2014. Antihistamines and birth defects: a systematic review of the literature. Expert opinion on drug safety. 13.12: 1667-1698. [PMC free article: PMC4474179] [PubMed: 25307228]
• Hansen Craig, et al. 2020. Use of antihistamine medications during early pregnancy and selected birth defects: The National Birth Defects Prevention Study, 1997–2011.  Birth defects research. 112.16: 1234-1252. [PMC free article: PMC9168970] [PubMed: 32657014]
• Ito S, et al. 1993. Prospective follow-up of adverse reactions in breast-fed infants exposed to maternal medication. Am J Obstet Gynecol. 168:1393-1399. [PubMed: 8498418]
• Kallen B, Mottet I. 2003. Delivery outcome after the use of meclozine in early pregnancy. Eur J Epidemiol. 18:665-669. [PubMed: 12952140]
• Katselou M, et al. 2018. A fully validated method for the simultaneous determination of 11 antihistamines in breast milk by gas chromatography-mass spectrometry. Biomed Chromatogr. 32(8):e4260. [PubMed: 29644705]
• Lenz W. 1966. Malformations caused by drugs in pregnancy. Am J Dis Child. 112:99-106. [PubMed: 5330368]
• Messinis IE, et al. 1985. Histamine H1 receptor participation in the control of prolactin secretion in postpartum. J Endocrinol Investig. 8:143-146. [PubMed: 3928731]
• Michaelis J, et al. 1983. Prospective study of suspected associations between certain drugs administered during early pregnancy and congenital malformations. Teratology. 27:57-64. [PubMed: 6845218]
• Mondillo C, et al. 2018. Potential negative effects of anti-histamines on male reproductive function. Reproduction. 155.5: R221-227. [PubMed: 29523718]